|Publication number||US6918550 B2|
|Application number||US 10/148,852|
|Publication date||Jul 19, 2005|
|Filing date||Sep 27, 2001|
|Priority date||Oct 4, 2000|
|Also published as||CN1392928A, DE10049034A1, DE10049034B4, DE50114663D1, EP1327070A2, EP1327070B1, US20040124278, WO2002029234A2, WO2002029234A3|
|Publication number||10148852, 148852, PCT/2001/3713, PCT/DE/1/003713, PCT/DE/1/03713, PCT/DE/2001/003713, PCT/DE/2001/03713, PCT/DE1/003713, PCT/DE1/03713, PCT/DE1003713, PCT/DE103713, PCT/DE2001/003713, PCT/DE2001/03713, PCT/DE2001003713, PCT/DE200103713, US 6918550 B2, US 6918550B2, US-B2-6918550, US6918550 B2, US6918550B2|
|Original Assignee||Robert Bosch Gmbh|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (14), Referenced by (5), Classifications (21), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to a fuel injector.
A fuel injector is described in German Published Patent Application No. 197 36 682 for direct injection of fuel into the combustion chamber of a mixture-compressing, internal combustion engine having externally supplied ignition, which has a guide and seating region at the downstream end of the fuel injector formed by three disk-shaped elements. In this connection, a swirl element is embedded between a guide element and a valve seat element. The guide element is used for guiding an axially movable valve needle reaching through it, while a valve closing section of the valve needle acts together with a valve seat surface of the valve seat element. The swirl element has an inner opening region having several swirl channels which are not in communication with the outer circumference of the swirl element. The entire opening region extends completely over the axial thickness of the swirl element.
It is particularly disadvantageous in the fuel injector known from the above-named document that gaps are created, during assembly of the swirl element, between the swirl element and the guide element, as well as between the swirl element and the valve seat element. This alters the metering cross section, whereby the dispersion of the static flow through the fuel injector is increased. This has a negative effect on the operation of the fuel injector because of differences in the metered fuel quantity per injection cycle.
By comparison, the fuel injector according to the present invention, having the characteristic features of the main claim, has the advantage that the valve seat element has a ring-shaped elevation on its end face on the fuel supply side facing the swirl element, and this elevation is higher than the unevenness of the surfaces of the valve seat element and the swirl element caused by manufacturing processes. Because of this, the gaps between the valve seat element and the swirl element arising from the assembly and subsequent heating during the operation of the fuel injector are reduced to a value fixed by the height of the ring-shaped elevation, which may compensated for by setting the static flow-through using other components, such as a setting device in the system of fuel supply.
Advantageous further developments of the fuel injector specified in the main claim are rendered possible by the measures given in the dependent claims.
In this context, of particular advantage is the design of a ring surface on the ring-shaped elevation, which makes the component part less sensitive to manufacturing tolerances.
It is also of advantage that the swirl element is clamped in between the guide element and the valve seat element during assembly, and therefore temperature changes during the operation of the fuel injector have no effect on the gap width or the quantity of metered fuel.
The fuel channels of the guide element are advantageously arranged in such a way that the fuel may run without hindrance and without disturbing throttle effects into the swirl channels and flow to the sealing seat.
The design of a swirl chamber is also of advantage, whose volume is selected, depending on the requirements, so that throttle effects may be eliminated.
The wedge-shaped areas at the end face of the valve seat element, bordering on the ring-shaped elevation, are easy to manufacture and, depending on the requirements, may be provided with any angles relative to a horizontal plane of reference.
The ring-shaped elevation may also be made in the shape of a ring which is attached to the end face of the valve seat element. The advantage of this embodiment variant is that one may take over the standard valve seat element without change.
Before exemplary embodiments of a fuel injector according to the present invention are described more precisely with reference to
Fuel injector 1 is designed in the form of an injector for fuel-injection systems of mixture-compressing internal combustion engines having externally supplied ignition. Fuel injector 1 is particularly suitable for directly injecting fuel into a combustion chamber (not illustrated) of an internal combustion engine.
Fuel injector 1 includes a nozzle body 2, in which a valve needle 3 is positioned. Valve needle 3 is connected in operative connection to a valve-closure member 4 that cooperates with a valve-seat surface 6, arranged on a valve-seat member 5, to form a sealing seat. Fuel injector 1 in the exemplary embodiment is an inwardly opening fuel injector 1 which has a spray-discharge opening 7. Nozzle body 2 is sealed from external pole 9 of a magnetic coil 10 by a seal 8. Magnetic coil 10 is encapsulated in a coil housing 11 and wound on a bobbin 12 which lies adjacent to an internal pole 13 of magnetic coil 10. Internal pole 13 and external pole 9 are separated from each other by a gap and are supported on a connecting component 29. Magnetic coil 10 is energized via an electric line 19 by an electric current which can be supplied via an electrical plug-in contact 17. Plug-in contact 17 is enclosed in a plastic jacket 18, which may be sprayed onto internal pole 13.
Valve needle 3 is guided in a valve needle guide 14, which is designed as a disk. A paired adjustment disk 15 is used to adjust the (valve) lift. An armature 20 is on the other side of adjustment disk 15. It is connected by force-locking to valve needle 3 via a first flange 21, and valve needle 3 is connected to first flange 21 by a welded seam 22. Braced against valve needle 21 is a return spring 23 which, in the present design of fuel injector 1, is prestressed by a sleeve 24.
A second flange 31, which is connected to valve needle 3 via a welded seam 33, is used as lower armature stop. An elastic intermediate ring 32, which lies upon second flange 31, avoids bounce when fuel injector 1 is closed.
Fuel channels 30 a through 30 c run through valve needle guide 14, armature 20 and valve seat member 5, which guide the fuel, supplied via central fuel supply 16 and filtered by a filter element 25, to spray-discharge opening 7. Fuel injector 1 is sealed by seal 28 from a fuel line (not shown).
In the neutral position of fuel injector 1, return spring 23 acts upon armature 20 counter to its lift direction in such a way that valve-closure member 4 is retained in sealing contact against valve seat 6. Upon excitation of magnetic coil 10, the latter generates a magnetic field which moves armature 20 in the lift direction, counter to the spring force of return spring 23, the lift being predefined by a working gap 27 existing in the neutral position between internal pole 12 and armature 20. Armature 20 also carries along in the lift direction flange 21, which is welded to valve needle 3. Valve-closure member 4, being connected to valve needle 3, lifts off from valve seat surface 6, and fuel guided via fuel channels 30 a through 30 c to spray-discharge opening 7 is sprayed off.
When the coil current is switched off, after sufficient decay of the magnetic field, armature 20 falls away from internal pole 13 because of the pressure of return spring 23, whereupon flange 21, being operatively connected to valve needle 3, moves in a direction counter to the lift direction. Thereby valve needle 3 is moved in the same direction in which valve-closing body 4 sets down upon valve seat surface 6, and fuel injector 1 is closed.
In an extract cross section,
The spray-off end of fuel injector 1 according to the present invention shown in
Guide element 31 has fuel channels 30 c which correspond to swirl channels 33 formed in swirl element 32.
Swirl element 32 is preferably formed disk-shaped at constant thickness, and lies on the fuel-supply side of end face 35 of valve seat element 5. Because of ring-shaped elevation 36, unevennesses due to manufacturing technology of swirl element 32 as well as of fuel-supply side end face 35 of valve seat element 5 are reduced to a gap 40 having a defined width. The width of gap 40 between valve seat element 5 and swirl element 32 may here amount to about 7 μm. The diameter of ring-shaped elevation 36 is selected in this case so that it intersects swirl channels 33 of swirl element 32. Elevation 36 may also be formed to be partially ring-shaped, and interrupted in the area of swirl channels 33. The diameter may here be 3.0 mm, for example. Ring-shaped elevation 36 may either be produced as one piece with valve seat element 5 by slanting fuel-supply side end face 35, a wedge-shaped surface 38 being formed, which drops off towards an outer side 37 of valve seat element 5. However, it is also possible to produce ring-shaped elevation 36 by positioning a ring-shaped structure on valve seat element 5. In that case, ring-shaped elevation 36 is connected to valve seat element 5 by soldering or welding.
When fuel injector 1 is operated, valve needle 3 is moved counter to a flow direction of the fuel, whereby valve-closure member 4 lifts off from valve seat surface 6, and fuel is sprayed off through fuel channels 30 c, swirl channels 33 and spray-off opening 7.
To make the measure according to the present invention clearer,
To clarify ring-shaped elevation 36, two broken lines A and B are introduced in FIG. 2B. Ring-shaped elevation 36 is here illustrated exaggeratedly high. Wedge-shaped surface 38 becomes lower towards radially outer region 37 of valve seat element 5 by about 7 μm over the diameter of valve seat element 5, which is made clear by the distance between lines A and B in FIG. 2B. The form of valve seat surface 6 as well as downstream structures such as spray-off opening 7 are not changed by the measure according to the present invention.
In the same view as in
In contrast to
Between swirl channels 33 and valve-closure member 4 a swirl chamber 39 is formed. In this connection, the volume of swirl chamber 39 may be selected, according to the requirements on fuel injector 1 in such a way that either intended throttle effects appear because of a small diameter, or the throttle effects are completely eliminated by a greater volume of swirl chamber 39. The volume of swirl chamber 39, has to be dimensioned in any case so that the swirl flow generated by swirl channels 33 in swirl element 32 remains homogeneous and is not brought to a standstill even during the idle time between two injection cycles of fuel injector 1, since the injection properties would otherwise be influenced negatively.
According to the present invention, in the embodiment described above of valve seat element 5 of fuel injector 1, it may be achieved that gap 40 caused by unevennesses due to the manufacturing process, present between swirl element 32 and valve seat element 5, may be eliminated to the extent that a constant width of gap 40 is attained, and the increase in flow-through conditioned on this is compensated for by a suitable setting of the static flow-through in the system of fuel supply. As a result, overall only a very slight dispersion of the static flow-through still appears.
The present invention is not limited to the illustrated exemplary embodiment, and may also be used, for example, for equipment having other swirl elements 32 having more or fewer swirl channels 33 as for any embodiments of fuel injectors 1 having any actuators 10.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4179069||Apr 26, 1978||Dec 18, 1979||Robert Bosch Gmbh||Electromagnetically operated fuel injection valve|
|US5016819||Jul 20, 1989||May 21, 1991||Siemens-Bendix Automotive Electronics L.P.||Electromagnetic fuel injector having split stream flow director|
|US5076499||Oct 26, 1990||Dec 31, 1991||Siemens Automotive L.P.||Fuel injector valve having a sphere for the valve element|
|US5642862 *||Jul 28, 1995||Jul 1, 1997||Siemens Automotive Corporation||Fuel injection valve having a guide diaphragm and method for assembling|
|US5875972 *||Feb 6, 1997||Mar 2, 1999||Siemens Automotive Corporation||Swirl generator in a fuel injector|
|US5931391||Oct 2, 1997||Aug 3, 1999||Denso Corporation||Fluid injection valve|
|US6065692 *||Jun 9, 1999||May 23, 2000||Siemens Automotive Corporation||Valve seat subassembly for fuel injector|
|US6179227 *||Aug 10, 1999||Jan 30, 2001||Siemens Automotive Corporation||Pressure swirl generator for a fuel injector|
|US6382533 *||Oct 28, 1999||May 7, 2002||Robert Bosch Gmbh||Fuel injection valve|
|DE2725135A1||Jun 3, 1977||Dec 14, 1978||Bosch Gmbh Robert||Elektromagnetisches kraftstoff- einspritzventil fuer brennkraftmaschinen|
|DE19638201A1||Sep 19, 1996||Apr 2, 1998||Bosch Gmbh Robert||Fuel injection valve for IC engines|
|DE19736682A1||Aug 22, 1997||Feb 25, 1999||Bosch Gmbh Robert||Fuel injector for internal combustion engine|
|DE19927196A1||Jun 15, 1999||Mar 2, 2000||Bosch Gmbh Robert||Brennstoffeinspritzventil|
|DE19935263A1||Jul 27, 1999||Feb 1, 2001||Bosch Gmbh Robert||Brennstoffeinspritzventil|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7438242 *||Jul 22, 2005||Oct 21, 2008||Magneti Marelli Holding S.P.A.||Electromagnetically actuated fuel injector|
|US7607636 *||Oct 27, 2009||Continental Automotive Gmbh||Valve assembly for an injection valve and injection valve|
|US20060022072 *||Jul 22, 2005||Feb 2, 2006||Franco Ciampolini||Electromagnetically actuated fuel injector|
|US20070095947 *||Apr 15, 2004||May 3, 2007||Simone Sivieri||Injection nozzle with an improved injection function and method for producing an injection nozzle|
|US20070176132 *||Jan 24, 2007||Aug 2, 2007||Mauro Grandi||Valve Assembly For An Injection Valve And Injection Valve|
|U.S. Classification||239/585.1, 239/585.5, 239/533.3, 239/533.11, 239/533.2|
|International Classification||F02M61/16, F02M51/08, F02M61/10, F02B75/12, F02M61/18, F02M51/06|
|Cooperative Classification||F02B2075/125, Y02T10/123, F02M61/18, F02M61/162, F02M61/168, F02M51/0671|
|European Classification||F02M61/18, F02M61/16C, F02M51/06B2E2, F02M61/16H|
|Oct 21, 2002||AS||Assignment|
Owner name: ROBERT BOSCH GMBH, GERMAN DEMOCRATIC REPUBLIC
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LUFT, HEINZ;REEL/FRAME:013404/0161
Effective date: 20020918
|Jan 13, 2009||FPAY||Fee payment|
Year of fee payment: 4
|Mar 4, 2013||REMI||Maintenance fee reminder mailed|
|Jul 19, 2013||LAPS||Lapse for failure to pay maintenance fees|
|Sep 10, 2013||FP||Expired due to failure to pay maintenance fee|
Effective date: 20130719